Studies On Whitefly And Predatory Orius Minutus In Vegetable Fields

Whiteflies is a kind of important pest among crops planting such as vegetables etc in the greenhouse, large canopy and reveals. This paper differentiated two kinds whiteflies that arise in Shanxi vegetable fields in details, and illustrated the morphological characteristics and esterase enzyme table pictures at the same time.This paper recorded 108 kinds of 33 families hosts of Trialeurodes vaporariorum (westwood) in Shanxi fields, 6 kinds were new record hosts in china. Hosts of Bemisia tabaci(Gennadiud) had 66 kinds of 20 families, 7 kinds were new record hosts in china. Among them, 10 kinds hosts had been written down altogether except that 3 kinds are public new record hosts of two kinds whiteflies. Public hosts of two kinds whiteflies had 63 kinds of 20 families. Kidney bean, tomato, eggplant, cucumber, French gourd, pumpkin, potato etc. were mainly common crops that happened seriously in vegetable fields.Two generations of whitefly took place in one year. The beginning of August was the first peak period of adults and the first ten days of September was the second peak period. The peak of nymphs happened in the last ten days of August first, the second peak happened in the middle ten days and the last ten days of September.The author studied on preying handing time, preying effect of Orius minutus to whitefly different stages, and the pradation function and reaction of Orius minutus to whitefly every stage in different prey densities. The results showed that predatory function of Orius minutus to whitefly eggs, low instar nymphs and 3-rd instar nymphs accorded with Holling-II equation and had better praying on ability to them. Through investigation in the population dynamics of whitefly and its natural enemy Orius minutus in vegetable fields in Shanxi, it indicated that Orius minutus were accorded with whiteflies and had taken some function of controlling to the second generation whiteflies.The result of drug test showed, insect growth regulator luprofezin was clever and best to whiteflies, its efficacy could be up to more than 88%. The local optimum period for spying drug is the first ten days of August, because the control on whiteflies had the best result at this moment and helped to protect and utilize the natural enemy.